The present invention relates generally to sheet feeding apparatus and, more particularly, to sheet feeding apparatus for flat bed optical scanners.
Optical scanners are used to generate a data signal representative of an image of an object which is scanned. The data signal generated by an optical scanner is typically transmitted to a computer for storage in a suitable data storage medium such as a floppy disk or is used by the computer to produce a display image of the object.
Various types of optical scanners are currently commercially available, including drum scanners, hand-held scanners, and flat bed scanners. A flat bed scanner has a stationary, transparent plate upon which a document to be imaged is positioned face-down. An optical scanning head located below the plate moves from one end of the plate to the other in a "scanning pass". During a scanning pass, the document placed on the scanner support surface is illuminated by the scanning head which successively focuses images of "scan line" portions of the document on optical sensors. The optical sensors produce a data signal representative of those scan line images.
The type of object which is scanned with a flat bed scanner is typically a flat document such as a page of text or a photograph. When objects to be scanned are provided in sheet form of a uniform size, it is possible to use a sheet feeder in association with the scanner device to sequentially feed the sheets into registration with the transparent plate portion of the scanner.
Currently, most flat bed scanners are sold with sheet feeders available as optional attachments.